Heretofore, there has been known an applicator (a coating device) which comprises a cylindrical shell with a coating liquid storage chamber defined therein, a coating body such as a pen point and a writing tip secured to an opening portion formed in a distal end of the cylindrical shell, and a valve mechanism disposed between the coating body and the coating liquid storage chamber.
In a coating device of the type as described, a knock portion disposed on the cylindrical shell is knocked or pushed to move a movable member disposed in the coating liquid storage chamber and the movable member, in turn, moves a valve element to open the valve mechanism so that the coating liquid is ready to be discharged from the storage chamber to an object to be coated.
However, the conventional device has such problems that when the device is not used for a long period of time or when the cover member is left removed, the coating liquid stored in the coating body and between the coating body and an inner wall of the opening portion of the distal end of the cylindrical shell is prone to create a hardened substance, a gelled substance and a viscous substance due to evaporation of moisture and solvent thereby choking the flow passage for the coating liquid, and therefore, a smooth flow of the coating liquid is interrupted.
Various attempts and proposals have been made in order to solve the above problems.
For example, Japanese Utility Model Publication No. 2-309 of 1989 discloses a writing device with a side knock valve having a writing body with a valve element fixed thereto and capable of containing therein a liquid, and the writing body is slidably inserted in a cavity formed in a distal end of a cylindrical shell, and a pigment ink flow passage formed between an outer surface of the writing body and an inner surface of the distal end of the cylindrical shell, and at least a part of the resilient cylindrical shell is defined as a resilient body, the resilient body being displaced by knocking the cylindrical shell so that the valve element and writing body will be slidingly moved simultaneously.
With respect to this utility model publication, the coating body is slidingly moved simultaneously with the opening operation of the valve element which is made by knocking the cylindrical shell, for the purpose of flowing ink smoothly by recovering the ink flow passage, just in case the flow passage is choked with ink composition which has been hardened by drying, in such a manner as to peel off and/or crush the lumps of ink.
Although the writing device of the above utility model publication can recover a region of the coating liquid flow passage between the coating body and the inner wall of the distal end portion of the cylindrical shell, it is impossible for this device to recover a region of the coating liquid flow passage in the coating body which passage is choked with the hardened substance, gelled substance and viscous substance of the coating liquid.
This is especially true when the coating body is a writing/painting brush because when the coating liquid stored in the writing tip is hardened or gelled or becomes viscous, fibers constituting the writing tip are mutually adhered, thereby making it impossible to feed and coat the coating liquid smoothly.